The present invention relates to a semiconductor device, and particularly to a resin molded semiconductor device packaging element which is formed by sealing a semiconductor element within a resin.
FIG. 1 is a plan view of a conventional semiconductor device. In the drawing, a semiconductor element 1 has many electrodes 2 at the periphery thereof and is placed on a die pad 3. Leads 4 are provided around the semiconductor element 1 and are respectively connected to the electrodes 2 of the semiconductor element 1 by metal wires such as Au wires 5. The members such as the semiconductor element 1, the leads 4 and the like are sealed within a sealing resin with the outer ends of the leads exposed to form a package body 6. In FIG. 1, the sealing resin is not shown.
In the conventional packaged semiconductor device configured as described above, during the operation, heat is generated from the semiconductor element 1 and is transferred to the outside of the semiconductor device 1 through the leads 4 and the package body 6.
In such a packaged semiconductor device, since the size of the package body 6 increases as the number of the leads 4 increases, the leads 4 in the package body 6 become long and thin. This causes increases in the inductance of earth leads and power leads and creates a problem in that switching noise is generated during operation at a high speed, and malfunctions occur.
In addition, if the number of pins is increased, the heating value of the packaged semiconductor device 1 is increased owing to an increase in the degree of integration. However, since the epoxy resin or the like, which forms the package body 6, has low thermal conductivity, the heat generated from the semiconductor element 1 is insufficiently released from the packaged semiconductor device 1 and thus remains therein. There is thus a problem in that the use of a semiconductor element having a high heating value causes the occurrence of malfunctions by the an increase in the temperature of the semiconductor element 1, and thus a deterioration in reliability of the packaged semiconductor device occurs.
Further, when the package body having a multilayer structure is made of a ceramic material having a thermal conductivity which is higher than that of resins, the heat release properties and the electrical characteristics of the packaged semiconductor device formed can be improved. However, there is a problem in that the production cost of the packaged semiconductor device is increased owing to the high price of the ceramic material.